The Dreaded Orange Peel

[Bernard Kron]

After a series of increasingly successful paint jobs I’ve suddenly developed a serious re-appearance of orange peel. I have changed nothing that I am aware of – but obviously have begun doing something to cause this. I was shooting Plasti-Kote, a solid, light blue, from a rattle can over DupliColor white primer.

I have seen immaculate paint jobs done with every method, rattle can, airbrush, even brush painting, and all manner of materials, urethane, acrylic, lacquer, or enamel. I’m less interested in materials and delivery methods than the basic mistakes one can make that cause orange peel.

Light orange peel can be cured with a good polishing but serious orange peel is almost impossible to completely eradicate, particularly in corners and along moldings. The result is what passes for a good “3-foot paint job†but which can’t pass muster up close. This much I know. So what I’d like are your collective thoughts on the causes, techniques for avoidance, and to whatever degree possible, cures, for the dreaded orange peel.

Thanks in advance for a healthy airing out of this terrible subject!

Edited September 2, 2009 by gbk1

[Harry P.]

It's orange PEEL... not peal...

[Pete J.]

Orange peel is the result of paint drying before it has time to self level. There are a lot of causes that are variants from the "normal". An increase in temperature causes it to dry faster. Spraying from a greater distance makes it arrive at the surface dryer. A slight reduction in the ratio of paint to thinner has the same outcome. Using a different quicker drying (lower temperature) solvent also causes the effect. Once you have identified the culprit, the the solution becomes obvious. As a general rule, I would suggest getting your delivery mechanism(airbrush or can) closer to the model and move faster to prevent drips and runs. Kind of basic, but that is a quick once through.

[chrismooney]

This used to bother me also. Then I looked at 8 out of 10 real cars and there is more orange peel in the paint then a Phoenix street corner.... So I just rub out my paint the best I can and enjoy my stress free work..... LOL I know not the answer you’re looking for but just another way to look at your problem.

[E St. Kruiser50]

Orange peel is the result of paint drying before it has time to self level. There are a lot of causes that are variants from the "normal". An increase in temperature causes it to dry faster. Spraying from a greater distance makes it arrive at the surface dryer. A slight reduction in the ratio of paint to thinner has the same outcome. Using a different quicker drying (lower temperature) solvent also causes the effect. Once you have identified the culprit, the the solution becomes obvious. As a general rule, I would suggest getting your delivery mechanism(airbrush or can) closer to the model and move faster to prevent drips and runs. Kind of basic, but that is a quick once through.

I agree with most everything said here by PETE.

Every temp. and humidity level has it's own share of challanges, and systems for sucess.

Bernard, get yourself the biggest package of white styrene picnic spoons you can find, and start shooting SAMPLES to find what works best for you.

THROWING THE SPOONS AWAY IS PAIN-FREE .

Usually, as Pete has stated here, ORANGE PEEL (Just for you HARRY ) is usually caused by the paint applicator, air-brush or spray can, being held too far away and paint drying too much before touching the surface.

Every coat after that just compounds the problem, and adds to it, and emphasises the appearance of the orange peel even more.

Also, waiting too long between coats also hinders the paint from flowing properly.

Each coat of paint should contribute to the two or three coats of paint underneath, to flowing well and smoothly together.

I always shoot three coats of color or clear - light, medium, heavy - 15 minutes apart.

If your clearing, 15 minutes after the last color coat, shoot one medium coat of clear for a "SEALER".

Wait and hour, and then do the three steps with the clear, at least once.

TOO MUCH PAINT YOU SAY ??? - TRY IT BEFORE YOU JUDGE.

OBVIOUSLY, WEATHER CONDITIONS MAKE A HUGE DIFFERENCE.

A stable spraying enviornment is what will give you the best repeatable results.

Unfortunately, most shoot out-doors and deal with the "ELEMENTS", which brings us full-circle to where we started with the "SPOONS .

NONE OF THE PAINTS IN MY SYSTEM OF PAINTING ARE EVER ALLOWED TO DRY, USUALLY MORE THAN AN HOUR, AND ALWAYS STAY IN THAT 24 HOUR WINDOW OF TIME.

EVERTHING IS PAINTED WET-IN-WET, AND "NOTHING" IS ALLOWED TO DRY UNTIL THE "VERY LAST COAT".

[Nick Winter]

Condition:

Dimpled surface, like the skin of an orange, resulting from paint droplets drying too much to level out and flow smoothly together (poor coalescence)

Cause:

1. Improper gun adjustment and techniques.

2. Extreme shop temperature causing the droplets to lose more solvent and dry out before they can flow and level properly.

3. Improper drying by gun fanning causing the paint droplets to dry out before they have a chance to flow together.

4. Improper flash or drying time causing subsequent coats to lose solvents to the dry coat.

5. Wrong thinner or reducer, or too little thinner or reducer.

6. Poor mixing of materials.

Prevention:

1. Use proper gun adjustments, techniques, and air pressure.

2. Schedule painting to avoid temperature and humidity extremes. Select thinner or reducer that is suitable for existing conditions. Use a slower evaporating thinner or reducer to overcome this.

3. Allow sufficient flash time. Do not dry by fanning.

4. Allow proper dry time for undercoats and topcoats.

5. Use the correct thinner and reducer in correct amounts for existing shop conditions.

6. Mix all pigmented coatings thoroughly.

Remedy:

In mild cases, a mild polishing compound for enamel or rubbing compound for lacquer may help. In severe cases, sand and refinish with a slower evaporating thinner or reducer at the correct air pressure.

[BigGary]

Dave, your just supposed to warm it until its warm to the touch, not hot! I just run hot water over the can a few minutes to warm it up.

Shake it real good and it should be ready if you have a clean nozzle.

I just pulled a '67 Coronet out of the purple pool last night after my paint job went to the crapper. I tried polishing out the Orange peel, but there was too much. I'll try again next warm day with an airbrush.

Gary

[Bernard Kron]

Thanx for the evolving discussion, guys. This is what I hoped to see. The Treehuggers' points, expressed in other threads as well, are/have been very helpful. Overall, I think smooth paint is the result of proper mix of the paint's components (Dave Z's point about shaking the can very well - I am finding that a good indicator is that I can't stand shaking it anymore ), optimum and consistent working temperature of both the surface to be painted and the paint itself, and - this from The Treehugger - possibly giving the paint layers the "chance" to dissolve or combine into each other (that's my theory anyway as to why Treehugger Dave gets such good results from a short interval between layers).

Interestingly, the problem that caused me to start this thread was the one problem I never considered - a defective paint nozzle. As soon as I switched to another can of clear (this is the point at which the orange peel problem popped up) the problem largely went away.

What seems to work well for me is to pre-heat both the paint (in a pan of warm tap water to the point where the whole rattle can surface is warm to the touch - so far I haven't had problems with bulging cans) and the paint surface (I use a dehydrator set to 105 degrees F), painting rapidly across and past the surace and immediately sending the object to the dehydrator to maintain the working temperature. I find the warmth of the dehydrator promotes flow of the paint and helps avoid the "chocolate dipped look" and allows thin coats.

Lately I've been trying The Treehugger's tip of working quickly from layer to layer. I use DupliColor and PalstiKote lacquers (?) and, using the dehydrator, they set up very quickly and that by the time I have heated the rattle can back to temperature it's ready for another coat. The one thing I haven't tried yet is to go directly to clear coat during the paint cycle. I still color sand the hardened color coat (4-8 hours in the dehydrator). Since the color coats are relatively smooth and the application of another coat while the prior coat is still relatively soft allows them to bond together more completely, I will definitely try cycling out to final clear with an upcomng paint job. If the color coats are good enough I suspect this should work very well.

But the bottom line is to be patient and methodical in the technique that works for you. For me, this is all still a matter of discipline. Someday I hope it will be a habit.

[kyledr330]

Bernard, here is a before and after pic for you. I had the same problem with Plasti-Kote primer under Dupli-color paint. My soloution to this problem is to buff out your paint job. I used 2000 grit sand paper to start and ended with 8000. The first pic was a before sanding, the second pic is the outcome of sanding. Please be nice these pics were shot at high ISO with macro so you are going to see every little "bad" thing.

[Bernard Kron]

Bernard, here is a before and after pic for you. I had the same problem with Plasti-Kote primer under Dupli-color paint. My soloution to this problem is to buff out your paint job. I used 2000 grit sand paper to start and ended with 8000. The first pic was a before sanding, the second pic is the outcome of sanding. Please be nice these pics were shot at high ISO with macro so you are going to see every little "bad" thing.

Your results are very nice indeed. The orange peel that prompted this thread was far worse than yours. I still color sand and generally work from 4000 to 12000 unless the orange peel is seriously bad in which case I try not to get below 3200. For sure, color sanding provides a great base for the clear coat. I'm still intrigued by Treehugger Dave's method of allowing layers of paint to combine by painting when the prior layer is still relatively soft. The assumption, of course, is that the prior coat is relatively smooth, of course!

Edited October 7, 2009 by gbk1

[E St. Kruiser50]

Hey Bernard

One of the things that I have realized reading the posts on a lot of different subjects here, is that we all learn how to do all these model building skills and techniques differently.

One of the constants though, is that to do ANYTHING WELL or even better, you have to PRACTICE, PRACTICE, PRACTICE, AND THEN MORE PRACTICE .

First of all, painting to me isn't just something I spray on a plastic piece, there's the mechanics of the paint, the chemistry, compatibility, timing, technique and enviorenment.

Sounds like a lot to think about all at once, but after a while it becomes second nature, and necessary for repeatably good results.

I CAN SPRAY "HOT LACQUERS OVER ENAMELS" REPEATABLY WITH NO ATTACKING because I understand those 6 things I just mentioned above.

The HOLLYWOOD GRAHAM that won at Salt lake has 36 coats of paint and I NEVER TOUCHED IT WITH SANDPAPER - EVER.

HAVEN'T SANDED COLOR OR CLEAR, OR STRIPPED A PAINT JOB IN 10 YEARS because I understand those 6 characteristics for painting and for repeatable success.

All my paint jobs are finished within 24 hours or over-lapping 24 hour periods for multi-color paint schemes.

The "LIL' HEBBY" I painted last Friday, including clear-coat in one hour total. By Saturday afternoon it was rubbed out and totally foiled.

LIST OF THINGS I DO DIFFERENTLY

(1)Spray in a heated spray booth.

(2)Spray at atleast 80 degrees.

(3)ALWAYS use a fresh can of paint when rattlecanning a complete body and it's body parts.

(4)ALWAYS use my air-brush at 65 - 85 PSI.

(5)NEVER let the paint dry more than an hour between coats.

(6)ALWAYS rub out the paint within 24 hours.

(7)ALWAYS spray wet-in-wet, even the clear over the color coat.

(8)NEVER get afraid of trying something new.

Every skill I learned came with great difficulty and challanges to my abilities and my personality, but the rewards were ALWAYS WORTH IT.

[Modelmartin]

The HOLLYWOOD GRAHAM that won at Salt lake has 36 coats of paint and I NEVER TOUCHED IT WITH SANDPAPER - EVER.

(4)ALWAYS use my air-brush at 65 - 85 PSI.

Holy cow! 36 coats!!!! Why?

I'm just teasing, Dave!

And people thought I was Gonzo airbrushing at 40 PSI!

Seriously, though and this is just my opinion on this overall topic, I never use a spray can to paint any part of my models. I hate them. They are expensive and waste so much paint. You have no control over the paint. The thought of trying to spray one of my models with a can makes me ill. I do not know why a serious adult model builder would still use spray cans. It's a mystery to me.

With an airbrush, if it is giving you some orange peel you can add some thinner, lower the pressure, move in closer without dousing your model with blast from the spray can"nozzle". Using a spray can is like painting a real car with a sprayer on your garden hose!!!

I'm just saying and it's just me.

[E St. Kruiser50]

I do not know why a serious adult model builder would still use spray cans. It's a mystery to me.

LOT'S OF MYSTERIES IN LIFE

Good thing I'm not a serious model builder, as I LOVE "SQUIRTING WITH RATTLE CANS".